CVE-2021-31617
📋 TL;DR
This vulnerability in Stormshield Network Security (SNS) ASQ allows remote attackers to execute arbitrary code due to improper memory management. It affects multiple versions across SNS product lines. Attackers can potentially take full control of affected firewall devices.
💻 Affected Systems
- Stormshield Network Security (SNS)
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with attacker gaining root privileges, installing persistent backdoors, pivoting to internal networks, and exfiltrating sensitive data.
Likely Case
Remote code execution leading to firewall compromise, network traffic interception, credential theft, and lateral movement within the network.
If Mitigated
Limited impact if firewalls are properly segmented, have strict access controls, and intrusion detection systems are monitoring for anomalous behavior.
🎯 Exploit Status
CVSS 9.8 indicates critical severity with network attack vector and no authentication required. Memory corruption vulnerabilities often lead to reliable exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions 2.7.9, 2.16.1, 3.7.21, 3.11.9, and 4.2.3 or later
Vendor Advisory: https://advisories.stormshield.eu/2021-020/
Restart Required: Yes
Instructions:
1. Download appropriate firmware update from Stormshield portal. 2. Backup current configuration. 3. Apply firmware update via web interface or CLI. 4. Reboot device. 5. Verify version is patched.
🔧 Temporary Workarounds
Disable ASQ Module
allTemporarily disable the vulnerable ASQ module to prevent exploitation
# Via CLI: configure
# system asq disable
Restrict Network Access
allLimit access to SNS management interfaces to trusted IPs only
# Configure firewall rules to restrict access to management IPs
🧯 If You Can't Patch
- Isolate affected devices in separate network segments with strict access controls
- Implement network monitoring and IDS/IPS rules to detect exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check current firmware version via web interface (System > Information) or CLI command 'show version'Check Version:
show versionVerify Fix Applied:
Verify firmware version is 2.7.9+, 2.16.1+, 3.7.21+, 3.11.9+, or 4.2.3+📡 Detection & Monitoring
Log Indicators:
- Unusual process creation, memory allocation errors, ASQ module crashes, unexpected reboots
Network Indicators:
- Unusual outbound connections from firewall, traffic to unexpected destinations, protocol anomalies
SIEM Query:
source="stormshield" AND (event_type="crash" OR event_type="memory_error" OR module="ASQ")